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Google image search profile

Assigned to



JavaScript: GC
4 months ago
22 days ago


(Reporter: Filip Andrei, Assigned: farre)


(Blocks: 2 bugs)

55 Branch
Windows 10
Dependency tree / graph

Firefox Tracking Flags

(Not tracked)


(Whiteboard: [qf:p2][QRC][QRC_Analyzed] , URL)



4 months ago
1.Access google.ro
2.Search for fox
3.Start Gecko profile
4.Click images 
5.Share profile

Gecko profile:
Blocks: 1362062

Comment 1

3 months ago
Miko, could you help to have first profiling? Thanks.
Assignee: nobody → mikokm
Flags: needinfo?(mikokm)
Although the profile display list creation times are pretty high (>5ms), nothing really stands out.

Filip: Would it be possible to get the profile with a higher sampling interval than 1ms (for example 0.3ms)?
Flags: needinfo?(mikokm) → needinfo?(afilip)

Comment 3

3 months ago
Hi Miko here is the profile with 0.3 interval :http://bit.ly/2u45jCE
Flags: needinfo?(afilip)
(In reply to Filip Andrei from comment #3)
> Hi Miko here is the profile with 0.3 interval :http://bit.ly/2u45jCE

Thank you. Unfortunately, the profile seems to be still missing some data, for example the segment here: https://perf-html.io/public/9325a584e58d90662b7762f1db976f86c78bb52f/calltree/?hiddenThreads=&implementation=cpp&invertCallstack&range=4.1584_8.9250~6.0152_8.5511~6.6596_6.6793&thread=2&threadOrder=0-2-3-5-1-4 is 20ms, but only 1.5ms is accounted for.
Could you please try increasing the profiler buffer size to something like 50MB to see if it makes a difference?
Flags: needinfo?(afilip)

Comment 5

3 months ago
I modified the buffer size to 540 mb and that is the max size i have on the Acer hardware

Flags: needinfo?(afilip)


3 months ago
Flags: needinfo?(mikokm)
Thank you Filip. Based on these profiles, there does not seem to be any obvious optimization opportunities.
Assignee: mikokm → nobody
Flags: needinfo?(mikokm) → needinfo?(afilip)

Comment 7

3 months ago
filip, could you help to provide more clues to show the performance issue? Or we could close the bug and wait another symptom shows up. Thanks.

Comment 8

3 months ago
I tooked another profile where i think that the slow response is more evidenced and the only based criteria is that is a lot slower than Chrome.Can you please take a look at this https://perfht.ml/2sosV3L.
Flags: needinfo?(afilip)

Comment 9

2 months ago
David, could you help to follow Filip's new profile in Comment 8? Thanks.
Assignee: nobody → dvander
Flags: needinfo?(dvander)
I don't really see anything actionable in this profile. It looks like the content process wants some information about cookies and is waiting for the UI to reply. The UI is spending a good deal of time running UI javascript and doing UI reflows/paints. Maybe "why do cookies need to contact the main thread" is a valid question, but maybe there is also a scheduling problem in the parent process.
Assignee: dvander → nobody
Flags: needinfo?(dvander)


2 months ago
Depends on: 1382701
Filip, is it possible you were experiencing page faults when you took the profile in comment 8? How much RAM do you have and how many tabs do you think you had open?
Here's a profile of the steps in comment 0 with tweaked dom.ipc.processCount prefs so that there's only one content process, and the profiling interval set to 2ms.
These settings seem to produce profiles that have fewer gaps in them.


I've also enabled stylo.
Andreas, could you also help to continue the investigation? Thanks.
Assignee: nobody → afarre
Flags: needinfo?(afarre)

Comment 14

2 months ago
I'm currently on PTO. Can help out in the week after next. Keeping the needinfo set to remind me.
Hi Andreas, could you help the profiling? thanks.

Comment 16

25 days ago
I re-ran the test on the Acer hardware, again with profile interval set to 2 ms:


and I see a bunch of GeckoMain delays as well as a bunch of Content delays. If I'm reading the profile correctly the reasons seems to be ipc waiting for GC, CC, painting. Not sure what more to say.
Flags: needinfo?(afarre)
tracking under quantum flow
Component: General → JavaScript: GC
Whiteboard: [QRC][QRC_NeedAnalysis] → [qf][QRC][QRC_Analyzed]
Whiteboard: [qf][QRC][QRC_Analyzed] → [qf:p2][QRC][QRC_Analyzed]
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